Traditionally, disperse dyes are used for dyeing synthetic fibers and its blend with other fibers such as cellulose, polyurethane, nylon and wool by usual exhaust dyeing, continuous dyeing and printing techniques.
Recently with changing trends, fashion and market requirement consumption of blended fabrics is significantly increased. These new fabrics are made out of micro size fiber using fine denier polyester fiber or blending fiber with polyurethane, nylon and wool. The fastness properties of these new colored fabrics become worse in light fastness and sublimation fastness, particularly washing fastness when dyed or printed with conventional disperse dyes. The fastness properties worsen due to thinning of dyed fiber by using fine denier polyester fiber or blending fiber with polyurethane, nylon and wool. The excellent dyestuff to endure this use is desired in this dyeing and printing field.
IN190551 and its divisional patents IN197577 and IN196765 disclose monoazo dyes containing fluorosulphonyl group. The aforesaid Indian Patents disclose process for colouring synthetic textile material or fiber blend.
The patent application 2162/KOLNP/2009 which is published as WO 2008/074719 discloses disperse dye mixture comprising (a) two or more disperse dyestuffs of the formula (I). GB 909843 also discloses novel azodyes. However, the dyes disclosed in GB 909843 are unable to provide solutions to the highly sophisticated micro fiber blends.
Thus the prior art discloses azo dye compounds and process for preparation, however does not impart excellent fastness properties particularly Light Fastness and Washing Fastness properties.